Agreed. I’d even wonder if fewer trains could make it work. I know that’s not ideal, but it feels worth it if you do like Dulles, one of the Restons, Tysons, East Falls Church, Rosslyn. Probably not possible after that with the blue and orange lines. Someone other than WMATA should math this.

I like to shit on the time it takes to get from Dulles to the city (example: Rosslyn to Largo is quicker than Rosslyn to Dulles, even with significantly more stops going to Largo and three lines of congestion). But you show a great contrast - it took me 90 min to get from Shirlington to the South Capitol Street exit on 395 this weekend. I can’t imagine what a drive from Dulles would have taken.

You’re ignoring the trains in front of the hypothetical express train. It’s not possible without new tracks unfortunately. WMATA did a study on doing it with existing infrastructure, and it saves 6 minutes. Huge oversight IMO, it would have been worth the cost.